In a magnetic disk device in which a plurality of magnetic disks in which a magnetic recording layer is formed on a circular plate are rotated, and writing of information to the magnetic recording layer of the magnetic disk and reading of the information from the magnetic recording layer are performed using a magnetic head, vibration of the magnetic disk by an air flow generated due to the rotation of the magnetic disk (flutter phenomenon) becomes a problem. Therefore, a rectifying component for adjusting an air flow on the magnetic disk is used. As the rectifying component, a rectifying component made of a metal has been conventionally used. However, a rectifying component made of a resin is being studied in consideration of a high cost of the rectifying component made of a metal and a concern about generation of metal contaminants (for example, Japanese Unexamined Patent Publication No. 2008-90874). The rectifying component made of a resin is superior to a rectifying component made of a metal in that the rectifying component made of a resin is allowed to be processed with high precision at low cost and metal contaminants are not generated.